Moves Shell::maximize_mode_controller() to WmShell

ash/mus/bridge/wm_shell_mus.cc

Index: ash/mus/bridge/wm_shell_mus.cc
diff --git a/ash/mus/bridge/wm_shell_mus.cc b/ash/mus/bridge/wm_shell_mus.cc
index 55b34d6620f90e2766e1fc54937415053d444d6d..1e1aa3d87f9c011dc4eebc058fa3d30dae7c9d9e 100644
--- a/ash/mus/bridge/wm_shell_mus.cc
+++ b/ash/mus/bridge/wm_shell_mus.cc
@@ -97,6 +97,8 @@ WmShellMus::WmShellMus(::mus::WindowTreeClient* client)
   client_->AddObserver(this);
   WmShell::Set(this);
 
+  CreateMaximizeModeController();
+
   CreateMruWindowTracker();
 
   accessibility_delegate_.reset(new DefaultAccessibilityDelegate);
@@ -104,6 +106,11 @@ WmShellMus::WmShellMus(::mus::WindowTreeClient* client)
 }
 
 WmShellMus::~WmShellMus() {
+  // This order mirrors that of Shell.
+
+  // Destroy maximize mode controller early on since it has some observers which
+  // need to be removed.
+  DeleteMaximizeModeController();
   DeleteSystemTrayDelegate();
   DeleteWindowSelectorController();
   DeleteMruWindowTracker();